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1. Activating reagents 2. Depressants 3. Others (they modify: pH, coagulation, redox, rheology, etc.) AUXILIARY FLOTATION REAGENT.

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Presentation on theme: "1. Activating reagents 2. Depressants 3. Others (they modify: pH, coagulation, redox, rheology, etc.) AUXILIARY FLOTATION REAGENT."— Presentation transcript:

1 1. Activating reagents 2. Depressants 3. Others (they modify: pH, coagulation, redox, rheology, etc.) AUXILIARY FLOTATION REAGENT

2 Activating action of hydrolyzing cations. Flotation of quartz in the presence of 10 –4 M sulfonate (no flotation in the absence of those cations)

3 Fluoric ions may activate and depress flotation of silicates: a – area of depressed flotation in presence of oleate b) area of activation in the presence of dodecylamine as collector (Manser, 1975)

4 Depressants acting through adsorption Depressing reagents Depressants acting through redox reactions Depressants acting through reactions with flotation reagents

5 Depressors acting through adsorption –MC + D = –MD + C D – depressant ion C – collector ion –MC – collector adsorbed or forming surface compound with mineral –MD – depressant adsorbed or forming surface compound with mineral Barski’s constant (relation) equilibrium const. for bulk reactions equilibrium const. for surface reactions general form of Barski’ relation

6 Depressants acting through adsorption pH modifiers (acids and bases)   k y    OH X based on attachment of partcles to bubble too high and low pH depress flotation of minerals

7   k y    OH X Values of parameter y for selected mineral-collector system (here pH regulator determines concentration of OH - ions (after Chander, 1988) Mineral–collector y pH range Galena/KEX –12 Galena/KDEDTP –9 Sphalerite/DEDTC –8 Sphalerite/DBDTC –10 Sphalerite/DADTC –11 Chalcopyrite/NaDEDTP –11 Chalcopyrite/KEX - 11–13 Pyrite/NaDEDTP –6 Pyrite/KEX - 10–12 E - ethyl, D – di, T tio, A- amyl, B- butyl, X- xanthate, P - phosphate, C – carbonate, K- potassium, Na - sodium In highly alkaline environment not working

8 Redox depressants

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10 Relationship between flotation recovery of sulfides and potential applied to a platinum wire immersed in aqueous suspension of a sulfide containing ethyl xanthate at 1.44·10 –5 kmol/m 3. After Richardson and Walker, 1985

11 Depressants acting through reactions with flotation reagents 2C 2 H 5 OC(S)SK + 2K 2 SO 3 + 2KHSO 3 + 2O 2  2C 2 H 5 OC(S)SOK  2C 2 H 5 OH + 4K 2 S 2 O 3 + 2CO 2 Removal of xathates from sulfides

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13 Dispersion modifiers iep Acids, bases, large organic ions


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